Compressor-unloading device



fNov.19,1929. QCiFAR MER 1,7s5,999

COMPRESSOR UNLOADING DEVICE Filed Aug. 5, 192'? "\(IVENTOR I CLYDE. c. FARME R BY%WM AT TORNEY Patented Nov.19, 1929.

fCLYDl o. ranrarin, 'or rrrrsBnnGr-r, rnNNsYLvAnrA, ASSIGNOR TO "THE vEs'r-rne- HOUSE 'ArR- nAKEco rANY, or WILMERDING, P NNsYLVANImA CORPORATION i or rENNsyL vamA ooMrREsson-UnLoAnrNo DEVICE 7 Application filed August 5, 1927.. eSer ia1' N'o.-210,844.'

This invention relates to fluid compressors, and 'morepa-r'ticularly to an unloading device for a fluid compressor.

The invention has special reference to a compressor which operates continuously, as distinguished fr in the type in which the compressor is stopped when the pressure of fluid 7 compressed by the compressor has been increased to a' predetermined degree and is, started when the pressure of fluid has been reduced to a predetermined degree. With a continuously operating compressor, it is necessary to provide an unloading device to relieve the compressor of its load when the pressure of fluid compressed has been increased to a predetermined degree, and the 1 principal object of my invention is to pro-; vide an improved compressor unloading de- 1 3-0 is provided withalug 31 having oppositely vice t the above type.

In the accompanylng drawing, thesingle figure is a sectional diagrammatic view of a commpressorand an unloading device there-- tor and embodying my invention.

A portion 1 of a fluid compressor cylinderis shown in the drawing, having the usual compressor piston 2 and provided with an inlet valve 3 and a discharge valve 4;, mounted in the cover plate 5.

The compressor discharges fluid ed by the compressor into a tank or reservoir I 6, by way of the discharge valve 4.

Disposed in the cover plate 5 is a flexible diaphragm 7 having the chamber 8 at one side connected by pipe 9 to the reservoir 6,

a pressure plate 10 engaging the diaphragm 7 is disposed in the chamber 11 atthe opposite.

, phragm 7 tends to operate, the lever 14, but the engagement of the roller 28with the inclined side of the diaphragm.

Pivotally fulerumed on lugs 12 carried by the diaphragm chamber cover plate 13 is a lever 14 and threaded into the short arm 15 of the lever is an adjustable screw 16 adapted to engage the outer face of a thimble 17 Interposed between the pressure plate 10 and the inner face of the thimble 17 is a ball 18 wvhich serves to transmit movement from the diaphragm 7 to the lever 14. The ball 18 permits relative movement of the parts and prevents cocking or jamming, such as might occur with the use of the ed position.

- A coil spring 19 having one end disposed in a recess in the cover plate 5, has its opposite end in engagement with a spring follower 20, movable ina recess in the long arm 21 of the lever 14, and engaging the follower is an adjustable screw 27.

Mounted in a recess in the cover plate 5 a which opens to the piston chamber 23 a relieli valve 2 1-, having an operatingstem 25, whichextends through a-bore in the cover plate and carries at its outer end a spring follower 26. Intel-posed between a flange of. the follower 26 and the cover plate5 is a coil spring27. f p

The outer end of the arm 21 extends downwardly andcarries a roller 28, and pivotally connected between lugs 29 carried by the cover plate 5 is an arm 30. The free end of the arm inclined faces 32, one or .theyotherof which is inengagement with t-he'roller 28, according as the lever 14 is in its loaded orits unload- A coil spring 88, has one end disposed in a recess in the cover plate 5 and the otherend engagesin a recess in the arm 30. a v 1 The upper end of the'valve stem is engageable by the head of an adjustable screw 34, compress.

which has screw-threaded engagement in the arm21; U i In operation,as the compressor operates to compress fluid into-the reservoir 6 in the usual manner, thepressurein chamber8 of the diaphragm 7 is increasedAl/Vhen the pressure hasbe'enincreasedsuificiently to overcome the opposing pressureof the spring 19, the diaface 32 of the arm '30 offers a momentary resistance to the-movement of the 'lever.', When;

the pressure in chamber 8 is suflicient to overa come this resistance, the roller 28 slips doWnwardly past the lug 31,so as to causea quick, snaplike action of the lever 14. The downward movement of leverel then-operates to;

the opening of the vent valve 24. a

The opening of -valve:24 connects piston cause' movement of the valve stem 26 andi to ates without compressing fluid and therefore without load.

When the pressure in'the reservoir 6 has been reduced to a predetermined degree, .the

spring 19 tends to move the lever 14 upwardly, but this movement is momentarily resisted by the engagement of the roller 28 with the lower inclined face 32 of the arm 80. When this resistance is overcome, the roller slips past the lug 31 with a quick, snaplike action, and then the upward movement of lever 14 permits the valve 24: to be closed by, the action of the spring 27 through the stem 26'. i

\Vithout this feature, therewould be a tendency-for the gradual increase in pressure on the diaphragm 7 to gradually move the lever let and cause a partial opening of the valve 2 f and thus a balanced condition might be ob- 30' I movable arm havingan inclinedface engaged by said lever, and a spring for opposing tained, such that the compressor would con-- tinue to operate at partial load.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: r 7 r 1. The combination with a fluid compressor, of means-for unloading the compressor comprising a pressure sensitive element subject to the pressure of fluid compressed by the compressor, a lever directly operated by said element, a valvedirectly operated by saidlever for unloading the compressor, a

1 movement of said arm by-said lever. I

'2. The: combination with a fluid compres- V movable in one direction by said element, a

ject to the pressure of fluid compressed by the compressor, a lever having one arm directly valve directly operated by the other arm of ysai-d'lever for unloading'the compressor, a

1 ivoted arm havin an inclined face en a ed V V a b -bya portion of said lever, and a spring for opposing movement'of said arm by said lever.

3. The combination with a fluid compressor, of means for unloading the compressor comprising apressure sensitive element sub- I I jectto the pressure of fluid compressed by the 1 compressor,a lever having one. arm directly i valve directly operated by the other arm ofsaid lever for unloading the compressor, a

movable in, one direction by said element, a

pivoted arm having one inclined face engaged by V a portion of said lever .when the lever the fulcrum, and a spring e g gi the lever V between the valve stem and the fulcrum.

5. A fluid compressor unloader comprising a fulcrumed lever, a pressure sensitive element sub ect to the pressure of fluid compressed and engaging said lever at one side of the fulcrum,- an unloading valve having a CLYDE o. FARMER.

stem engaging said lever at the other side of sor, of means for unloading the compressor comprising a pressure sens tive element sub- 'movesiin. one. direction and another inclined D faceengaged by a portion of saidlever when the lever moves 1n the 'opposlte d1rect1on,'an d by said lever. V p I 4. A fluid compressor unloader comprising a fulcrumed'lev'er, a pressure sensitive ele- "a springfor opposing movement of said arm ment subject to the pressure ofifluidcompressed and engaging said lever at one side of tl1efulcri1m,' an unloading valve having a stem'engaglng'saidleverat theother side of 

